Abstract:

A method for instrumenting a computer program, the method including
identifying a program slice within a computer program, and instrumenting
the program slice within the program.

Claims:

1. A method for instrumenting a computer program, the method
comprising:identifying a program slice within a computer program;
andinstrumenting said program slice within said program.

2. A method according to claim 1 wherein said identifying step comprises
identifying said program slice wherein said program slice includes fewer
than all of the statements in said computer program.

3. A method according to claim 1 wherein said identifying step comprises
identifying said program slice wherein said program slice includes any
statements in said computer program that meet at least one predefined
slicing criterion.

4. A method according to claim 3 wherein said identifying step comprises
applying said at least one predefined slicing criterion to include within
said program slice any statements in said computer program that directly
or indirectly relate to an action performed with a selected variable
before or after a specific point within said computer program.

5. A method according to claim 3 wherein said identifying step comprises
applying said at least one predefined slicing criterion to include within
said program slice any statements in said computer program that directly
or indirectly relate to a predefined input vector and entry point of said
computer program.

6. A method according to claim 1 wherein said instrumenting step comprises
applying at least one predefined instrumentation criterion to said
program slice.

7. A method according to claim 1 wherein said instrumenting step comprises
instrumenting said program slice within said computer program in a manner
that does not change the underlying functionality of said program that is
not related to said instrumentation.

8. A method according to claim 1 and further comprising executing said
instrumented program.

9. A system for instrumenting a computer program, the system comprising:a
program slicer configured to identify a program slice within a computer
program; andan instrumentation engine configured to instrument said
program slice within said program.

10. A system according to claim 9 wherein said program slicer is
configured to include within said program slice fewer than all of the
statements in said computer program.

11. A system according to claim 9 wherein said program slicer is
configured to include within said program slice any statements in said
computer program that meet at least one predefined slicing criterion.

12. A system according to claim 11 wherein said program slicer is
configured to apply said at least one predefined slicing criterion to
include within said program slice any statements in said computer program
that directly or indirectly relate to an action performed with a selected
variable before or after a specific point within said computer program.

13. A system according to claim 11 wherein said program slicer is
configured to apply said at least one predefined slicing criterion to
include within said program slice any statements in said computer program
that directly or indirectly relate to a predefined input vector and entry
point of said computer program.

14. A system according to claim 9 wherein said instrumentation engine is
configured to apply at least one predefined instrumentation criterion to
said program slice.

15. A system according to claim 9 wherein said instrumentation engine is
configured to instrument said program slice within said computer program
in a manner that does not change the underlying functionality of said
program that is not related to said instrumentation.

16. A computer program product for instrumenting a computer program, the
computer program product comprising:a computer readable medium;
andcomputer program instructions operative toidentify a program slice
within a computer program, andinstrument said program slice within said
program,wherein said program instructions are stored on said computer
readable medium.

17. A computer program product according to claim 16 wherein said computer
program instructions include instructions operative to identify said
program slice wherein said program slice includes any statements in said
computer program that meet at least one predefined slicing criterion.

18. A computer program product according to claim 17 wherein said computer
program instructions include instructions operative to apply said at
least one predefined slicing criterion to include within said program
slice any statements in said computer program that directly or indirectly
relate to an action performed with a selected variable before or after a
specific point within said computer program.

19. A computer program product according to claim 17 wherein said computer
program instructions include instructions operative to apply said at
least one predefined slicing criterion to include within said program
slice any statements in said computer program that directly or indirectly
relate to a predefined input vector and entry point of said computer
program.

20. A computer program product according to claim 16 wherein said computer
program instructions include instructions operative to instrument said
program slice within said computer program in a manner that does not
change the underlying functionality of said program that is not related
to said instrumentation.

[0002]Code instrumentation is a technique that allows computer software to
be monitored at runtime, such as to facilitate debugging efforts. For
example, software code may be instrumented by inserting instructions that
display debugging messages or that write information related to program
behavior to a log file. In this way software developers may learn about
the internal behavior of the software they write and identify aberrant
behavior.

[0003]The main drawback of code instrumentation is that it typically
requires a significant amount of resources, both in terms of memory and
of processing power. Typically, instrumentation engines insert
instructions into the entire code base of a software application,
resulting in bloated and sluggish code. Furthermore, instrumentation
engines typically employ only rudimentary logic to determine the parts of
a software application where instrumentation is both applicable and
desirable. For example, instrumentation engines often insert instructions
into parts of software code that are unreachable given an input vector
that is of interest during debugging, or even parts that are unreachable
under any conditions (i.e., dead code). More efficient code
instrumentation would therefore be advantageous.

[0005]In one aspect of the present invention a method is provided for
instrumenting a computer program, the method including identifying a
program slice within a computer program, and instrumenting the program
slice within the program.

[0006]In another aspect of the present invention the identifying step
includes identifying the program slice where the program slice includes
fewer than all of the statements in the computer program.

[0007]In another aspect of the present invention the identifying step
includes identifying the program slice where the program slice includes
any statements in the computer program that meet at least one predefined
slicing criterion.

[0008]In another aspect of the present invention the identifying step
includes applying the at least one predefined slicing criterion to
include within the program slice any statements in the computer program
that directly or indirectly relate to an action performed with a selected
variable before or after a specific point within the computer program.

[0009]In another aspect of the present invention the identifying step
includes applying the at least one predefined slicing criterion to
include within the program slice any statements in the computer program
that directly or indirectly relate to a predefined input vector and entry
point of the computer program.

[0010]In another aspect of the present invention the instrumenting step
includes applying at least one predefined instrumentation criterion to
the program slice.

[0011]In another aspect of the present invention the instrumenting step
includes instrumenting the program slice within the computer program in a
manner that does not change the underlying functionality of the program
that is not related to the instrumentation.

[0012]In another aspect of the present invention the method further
includes executing the instrumented program.

[0013]In another aspect of the present invention a system is provided for
instrumenting a computer program, the system including a program slicer
configured to identify a program slice within a computer program, and an
instrumentation engine configured to instrument the program slice within
the program.

[0014]In another aspect of the present invention the program slicer is
configured to include within the program slice fewer than all of the
statements in the computer program.

[0015]In another aspect of the present invention the program slicer is
configured to include within the program slice any statements in the
computer program that meet at least one predefined slicing criterion.

[0016]In another aspect of the present invention the program slicer is
configured to apply the at least one predefined slicing criterion to
include within the program slice any statements in the computer program
that directly or indirectly relate to an action performed with a selected
variable before or after a specific point within the computer program.

[0017]In another aspect of the present invention the program slicer is
configured to apply the at least one predefined slicing criterion to
include within the program slice any statements in the computer program
that directly or indirectly relate to a predefined input vector and entry
point of the computer program.

[0018]In another aspect of the present invention the instrumentation
engine is configured to apply at least one predefined instrumentation
criterion to the program slice.

[0019]In another aspect of the present invention the instrumentation
engine is configured to instrument the program slice within the computer
program in a manner that does not change the underlying functionality of
the program that is not related to the instrumentation.

[0020]In another aspect of the present invention a computer program
product is provided for instrumenting a computer program, the computer
program product including a computer readable medium, and computer
program instructions operative to identify a program slice within a
computer program, and instrument the program slice within the program,
where the program instructions are stored on the computer readable
medium.

[0021]In another aspect of the present invention the computer program
instructions include instructions operative to identify the program slice
where the program slice includes any statements in the computer program
that meet at least one predefined slicing criterion.

[0022]In another aspect of the present invention the computer program
instructions include instructions operative to apply the at least one
predefined slicing criterion to include within the program slice any
statements in the computer program that directly or indirectly relate to
an action performed with a selected variable before or after a specific
point within the computer program.

[0023]In another aspect of the present invention the computer program
instructions include instructions operative to apply the at least one
predefined slicing criterion to include within the program slice any
statements in the computer program that directly or indirectly relate to
a predefined input vector and entry point of the computer program.

[0024]In another aspect of the present invention the computer program
instructions include instructions operative to instrument the program
slice within the computer program in a manner that does not change the
underlying functionality of the program that is not related to the
instrumentation.

BRIEF DESCRIPTION OF THE DRAWINGS

[0025]The present invention will be understood and appreciated more fully
from the following detailed description taken in conjunction with the
appended drawings in which:

[0026]FIG. 1 is a simplified conceptual illustration of a system for
efficient instrumentation of computer-based software applications,
constructed and operative in accordance with an embodiment of the present
invention;

[0027]FIG. 2 is a simplified flowchart illustration of an exemplary method
of operation of the system of FIG. 1, operative in accordance with an
embodiment of the present invention; and

[0028]FIG. 3 is a simplified block diagram illustration of an exemplary
hardware implementation of a computing system, constructed and operative
in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0029]The present invention is now described within the context of one or
more embodiments, although the description is intended to be illustrative
of the invention as a whole, and is not to be construed as limiting the
invention to the embodiments shown. It is appreciated that various
modifications may occur to those skilled in the art that, while not
specifically shown herein, are nevertheless within the true spirit and
scope of the invention.

[0030]As will be appreciated by one skilled in the art, the present
invention may be embodied as a system, method or computer program
product. Accordingly, the present invention may take the form of an
entirely hardware embodiment, an entirely software embodiment (including
firmware, resident software, micro-code, etc.) or an embodiment combining
software and hardware aspects that may all generally be referred to
herein as a "circuit," "module" or "system." Furthermore, the present
invention may take the form of a computer program product embodied in any
tangible medium of expression having computer usable program code
embodied in the medium.

[0031]Any combination of one or more computer usable or computer readable
medium(s) may be utilized. The computer-usable or computer-readable
medium may be, for example but not limited to, an electronic, magnetic,
optical, electromagnetic, infrared, or semiconductor system, apparatus,
device, or propagation medium. More specific examples (a non-exhaustive
list) of the computer-readable medium would include the following: an
electrical connection having one or more wires, a portable computer
diskette, a hard disk, a random access memory (RAM), a read-only memory
(ROM), an erasable programmable read-only memory (EPROM or Flash memory),
an optical fiber, a portable compact disc read-only memory (CDROM), an
optical storage device, a transmission media such as those supporting the
Internet or an intranet, or a magnetic storage device. Note that the
computer-usable or computer-readable medium could even be paper or
another suitable medium upon which the program is printed, as the program
can be electronically captured, via, for instance, optical scanning of
the paper or other medium, then compiled, interpreted, or otherwise
processed in a suitable manner, if necessary, and then stored in a
computer memory. In the context of this document, a computer-usable or
computer-readable medium may be any medium that can contain, store,
communicate, propagate, or transport the program for use by or in
connection with the instruction execution system, apparatus, or device.
The computer-usable medium may include a propagated data signal with the
computer-usable program code embodied therewith, either in baseband or as
part of a carrier wave. The computer usable program code may be
transmitted using any appropriate medium, including but not limited to
wireless, wireline, optical fiber cable, RF, etc.

[0032]Computer program code for carrying out operations of the present
invention may be written in any combination of one or more programming
languages, including an object oriented programming language such as
Java, Smalltalk, C++ or the like and conventional procedural programming
languages, such as the "C" programming language or similar programming
languages. The program code may execute entirely on the user's computer,
partly on the user's computer, as a stand-alone software package, partly
on the user's computer and partly on a remote computer or entirely on the
remote computer or server. In the latter scenario, the remote computer
may be connected to the user's computer through any type of network,
including a local area network (LAN) or a wide area network (WAN), or the
connection may be made to an external computer (for example, through the
Internet using an Internet Service Provider).

[0033]The present invention is described below with reference to flowchart
illustrations and/or block diagrams of methods, apparatus (systems) and
computer program products according to embodiments of the invention. It
will be understood that each block of the flowchart illustrations and/or
block diagrams, and combinations of blocks in the flowchart illustrations
and/or block diagrams, can be implemented by computer program
instructions. These computer program instructions may be provided to a
processor of a general purpose computer, special purpose computer, or
other programmable data processing apparatus to produce a machine, such
that the instructions, which execute via the processor of the computer or
other programmable data processing apparatus, create means for
implementing the functions/acts specified in the flowchart and/or block
diagram block or blocks.

[0034]These computer program instructions may also be stored in a
computer-readable medium that can direct a computer or other programmable
data processing apparatus to function in a particular manner, such that
the instructions stored in the computer-readable medium produce an
article of manufacture including instruction means which implement the
function/act specified in the flowchart and/or block diagram block or
blocks.

[0035]The computer program instructions may also be loaded onto a computer
or other programmable data processing apparatus to cause a series of
operational steps to be performed on the computer or other programmable
apparatus to produce a computer implemented process such that the
instructions which execute on the computer or other programmable
apparatus provide processes for implementing the functions/acts specified
in the flowchart and/or block diagram block or blocks.

[0036]Reference is now made to FIG. 1, which is a simplified illustration
of a system for efficient instrumentation of computer-based software
applications, constructed and operative in accordance with an embodiment
of the present invention. In the system of FIG. 1, a program slicer 100
identifies a program slice 102 within a computer program 104 in
accordance with conventional program slicing techniques, such as where
static analysis techniques are used to identify statements within program
104 that meet one or more predefined slicing criteria 110. Slicing
criteria 110 may, for example, include within program slice 102 any
statements in computer program 102 that directly or indirectly relate to
an action performed with a selected variable before and/or after a
specific point within program 104, and/or that relate to a predefined
input vector and entry point of program 104. Preferably, program slice
102 includes fewer than all of the statements in computer program 104. An
instrumentation engine 106 applies one or more predefined instrumentation
criteria 108 to program slice 102 to determine what instrumentation is to
be inserted, as well as where to insert the instrumentation into program
slice 102 within program 104, and instruments program slice 102 within
program 104 accordingly. The instrumentation applied by instrumentation
engine 106 preferably does not change the underlying functionality of
program 104, such that the behavior of program 104 both before and after
instrumentation is identical when the behavior of the instrumentation is
disregarded.

[0037]In one embodiment any of the elements shown in FIG. 1 are
implemented as a computer program product embodied in a computer-readable
medium, such as in the form of computer program instructions stored on
magnetic or optical storage media or embedded within computer hardware,
and are executed by or otherwise accessible to a computer 112.

[0038]Reference is now made to FIG. 2, which is a simplified flowchart
illustration of an exemplary method of operation of the system of FIG. 1,
operative in accordance with an embodiment of the present invention. In
the method of FIG. 2, a program slice is identified within a computer
program in accordance with conventional program slicing techniques. One
or more predefined instrumentation criteria are applied to the program
slice to determine what instrumentation is to be inserted, as well as
where to insert the instrumentation into the program slice within the
program, and the program slice is instrumented accordingly within the
program. The program, together with the identified program slice and its
instrumentation, may be compiled if required and executed.

[0039]It will be appreciated that instrumenting only a program slice
within a program requires significantly less memory and processing power
than would instrumenting the entire program. Furthermore, instrumenting
an identified program slice greatly reduces the chance that unreachable
code will be instrumented.

[0040]Referring now to FIG. 3, block diagram 300 illustrates an exemplary
hardware implementation of a computing system in accordance with which
one or more components/methodologies of the invention (e.g.,
components/methodologies described in the context of FIGS. 1 and 2) may
be implemented, according to an embodiment of the present invention.

[0041]As shown, the techniques for controlling access to at least one
resource may be implemented in accordance with a processor 310, a memory
312, I/O devices 314, and a network interface 316, coupled via a computer
bus 318 or alternate connection arrangement.

[0042]It is to be appreciated that the term "processor" as used herein is
intended to include any processing device, such as, for example, one that
includes a CPU (central processing unit) and/or other processing
circuitry. It is also to be understood that the term "processor" may
refer to more than one processing device and that various elements
associated with a processing device may be shared by other processing
devices.

[0043]The term "memory" as used herein is intended to include memory
associated with a processor or CPU, such as, for example, RAM, ROM, a
fixed memory device (e.g., hard drive), a removable memory device (e.g.,
diskette), flash memory, etc. Such memory may be considered a computer
readable storage medium.

[0044]In addition, the phrase "input/output devices" or "I/O devices" as
used herein is intended to include, for example, one or more input
devices (e.g., keyboard, mouse, scanner, etc.) for entering data to the
processing unit, and/or one or more output devices (e.g., speaker,
display, printer, etc.) for presenting results associated with the
processing unit.

[0045]The flowchart and block diagrams in the Figures illustrate the
architecture, functionality, and operation of possible implementations of
systems, methods and computer program products according to various
embodiments of the present invention. In this regard, each block in the
flowchart or block diagrams may represent a module, segment, or portion
of code, which comprises one or more executable instructions for
implementing the specified logical function(s). It should also be noted
that, in some alternative implementations, the functions noted in the
block may occur out of the order noted in the figures. For example, two
blocks shown in succession may, in fact, be executed substantially
concurrently, or the blocks may sometimes be executed in the reverse
order, depending upon the functionality involved. It will also be noted
that each block of the block diagrams and/or flowchart illustration, and
combinations of blocks in the block diagrams and/or flowchart
illustration, can be implemented by special purpose hardware-based
systems that perform the specified functions or acts, or combinations of
special purpose hardware and computer instructions.

[0046]While the methods and apparatus herein may or may not have been
described with reference to specific computer hardware or software, it is
appreciated that the methods and apparatus described herein may be
readily implemented in computer hardware or software using conventional
techniques.

[0047]While the present invention has been described with reference to one
or more specific embodiments, the description is intended to be
illustrative of the invention as a whole and is not to be construed as
limiting the invention to the embodiments shown. It is appreciated that
various modifications may occur to those skilled in the art that, while
not specifically shown herein, are nevertheless within the true spirit
and scope of the invention.